The nutmeg tree, Myristica fragans which belong to the family Myristicaceae, is an 8-10 meter high evergreen tree that is cultivated in India, Indonesia and Ceylon. This tree bears two separate and distinct products which can be harvested all year long: nutmeg which is the kernel of the seed, and mace which is the dried aril that surrounds the single seed within the fruit. Nutmeg is a grayish brown, ovoid seed that is a well known spice used in food. Nutmeg essential oil is produced by steam distillation of the rip and dried nutmeg. The main components of nutmeg essential oil aresabinene (14-29%), α-pinene (15-28%), β-pinene (13-18%), limonene (2-7%), myristicin (5-12%), elemicin, eugenol, isoeugenol and safrole. Safrole is also known as [5-(2-propenyl)1,3-benzodioxole].
The use of safrole in food is limited due to its associated toxicity. The US Food and Drug Administration (FDA) has prohibited the use of safrole in human food. The Council of Europe has limited the use of safrole in food and beverages to less than 1 ppm. The International Agency for the Research on Cancer (IARC) describes safrole as carcinogenic in mice and rats, and possible carcinogenic to humans. The International Fragrance Association has prohibited the use of safrole as a fragrance ingredient and limits the use of safrole to not exceed 0.01% in consumer products. Isosafrole and dihydrosafrole which differ from safrole in the position of the side chain double bond and saturation of this side chain, respectively, are treated in the same manner as safrole by the aforementioned agencies.
One method for removing safrole from nutmeg oil is distillation. U.S. published patent application 2004/0047930 recites nutmeg oil derived from Grenada nutmegs. The nutmeg oil was purified via steam distillation and the resulting nutmeg oil comprised <0.5% safrole.
Molecular imprinting is a developing technique for the preparation of synthetic polymers containing recognition sites for certain target molecules and is described in U.S. Pat. No. 5,630,978 and U.S. published patent application 2004/0157209. Molecular imprinting is achieved by co-polymerizing functional monomers and cross-linking monomers in the presence of the target molecule, which acts as a molecular template. The functional monomers arrange specifically around the molecular template, and are subsequently held in position by polymerization with a usually high degree of cross-linking. After polymerization, the molecular template is extracted from the polymer, revealing complementary binding sites that allow rebinding of the target molecule with in many cases very high specificity, comparable to that of antibodies. U.S. published patent application 2004/0096979 describes imprinted polymers for detecting phenols, but does not discuss compounds such as safrole and the like.
The aroma of nutmeg essential oil is a unique combination of various flavor materials in specific amounts. What is needed is a method of removing safrole from nutmeg essential oil and other compositions, and in particular a method that preferably removes safrole while retaining the aroma and flavor of the nutmeg essential oil.